B. cereus-produced cereulide as an emetic toxin is commonly isolated in starch-based cooked foods. This study examined the prevalence of B. cereus from ready-to-eat foods in markets by polymerase chain reaction analysis and determined the relationship between the level of B. cereus and the quantity of cereulide in the sample after different storage times and temperatures. The prevalence of general B. cereus in 43 starch foods was 32.6%, and the level of B. cereus ranged from 0.5 to 1.95 log cfu/g, meeting the Korea Food Code Specifications of 3 log CFU/g of B. cereus. No samples revealed emetic B. cereus. Fried rice samples were inoculated with a cereulide-producing reference strain, B. cereus NCCP 14796, to determine the level of B. cereus and the quantity of cereulide in the samples after storage for 0, 4, 6, 8, 20, 24, 30, 48, 72, and 96 h at 7, 25, 35, and 57℃. The average levels of B. cereus at 7, 25, 35, and 57℃ were 4.38, 7.31, 7.88, and 3.82 log cfu/g, and the levels of cereulide were 150.41, 1680.70, 2652.65, and 77.83 ㎍/mL, respectively, showing a significant difference according to the incubation time (P<0.05) and temperature (P<0.001).